The present invention relates to a new and improved construction of apparatus for the continuous, zigzag-shaped folding of a material web or the like.
The folding apparatus of the invention is generally of the type comprising an infeed station for the material web and two conveying or feed gaps arranged following the infeed station at the outfeed or discharge portion thereof and located to respective opposite sides of said infeed station. The conveying gaps extend transversely and substantially parallely with respect to the direction of conveying of the material web by the infeed station. The conveying direction of the one conveying gap, in relation to the infeed station, is opposite to the conveying direction of the other conveying gap. Further, means are provided in order to reverse the conveying directions of both conveying gaps with respect to the infeed station.
Equipment of this type has become known to the art, for instance from German patent publication No. 2,134,898. In contrast to conventional pocket folding machines, where for the purpose of producing n-folds there are always required n plus 1 fold- or conveying gaps, which generally are formed by a roller frame containing n plus 2 rolls, equipment of the previously mentioned type possesses the advantage of being able to get by with only two folding- or conveying gaps, independent of the number of folds which are to be produced in one and the same material web. The prior art apparatuses of the previously mentioned type are equipped at the outfeed or discharge end of the infeed station with a return movement-blocking device which acts upon the material web. During the reversal of the conveying direction of the conveying or feed gaps, the section of the material web which is located between the reverse movement-blocking device and the one conveying gap, is forced to bendout or crease in the direction of the other conveying gap, in order to be seized and folded thereby. The state-of-the-art apparatuses of this type are only therefore poorly suitable for the zigzag-folding of a multi-layer material web, because the return movement-blocking device only is effective upon the outermost layer of such multi-layer material web. In particular, the prior art equipment is not suitable for further folding a material web which itself consists of a sheet folded in a zigzag-configuration in one direction, in a transversely extending direction, i.e. to form a cross-fold. Thus, for instance, with the heretofore known equipment of the prior art, while it is possible to fold large plans, such as shop or blue-prints, for instance of a size corresponding to DIN AO (German industrial standard AO) and larger in one direction in a zigzag-configuration to a smaller width, it is however not possible to further fold such sheet in a direction transverse thereto, because the "material web" which is available after the first series of folds has at its side edges the folds formed from the first folding operation, which tend to undesirably stiffen the material web in an unpredictable manner.